Tool guides are well known devices which provide a user control of a cutting instrument in precision applications. While various tool guides are known, tool guides which are adaptable for use on curvilinear or structures surfaces pose significant problems. This is because most known tool guides rely on nonadjustable linear supports which are not readily adapted for the generation of controlled complex movement.
Precise control of a cutting instrument is particularly important with structures constructed of composite materials which may be laminated in several layers. Each layer of a composite construction is typically formed with plies of carbon or fiberglass fiber material which is bonded to the other layers with a resinous material such as epoxy. This construction poses several problems in repairing damaged composite components while providing all the structural integrity of the original component, because loads in these materials are carried by the fiber layers and can be prone to delamination if damaged.
The repair of composite materials requires that any damaged area be removed, thus exposing each of the fiber layers for bonding to new material. Typically, damaged composite material is removed with a process known as scarfing. Scarfing provides a region surrounding a damaged area having beveled or angled walls to receive new composite material and provide a contact surface for each fiber layer. While known tools have been developed for scarfing flat surfaces, additional damage or alteration to the structure is incurred. These tools cannot be used with complex structures. Today, spherical or curved surfaces are scarfed by hand sanding and grinding.
One example of an apparatus for supporting a cutting instrument is shown in Soviet Union Inventor's certificate No. 537,762, issued 1977. This device is a router mounted on the end of a shaft, wherein the angle of the router is adjusted by an adjustment arm. While this device can create complex shapes, there is no provision for moving the router mechanism in a lateral direction. Furthermore, there is no provision to control the field of motion or depth of cut for the router assembly, and non-circular cutouts cannot be prepared
Another example of an apparatus for supporting a cutting instrument is shown in U.S. Pat. No. 2,638,136, issued 1953. This device includes a routing element which is supported with a plurality of cross supports over a work piece. In this invention, the cross support members restrict movement of the router to a single plane which is perpendicular to the cross support members. Therefore, this invention is not adapted for creating tapered or spherical shapes and is limited to curvilinear shapes. In addition, oval or non-circular cutouts cannot be prepared.
Still another example of an apparatus for supporting a cutting instrument is shown in U.S. Pat. No. 4,614,446, issued 1986. This invention produces a curvilinear cut following a specific radius determined by the rails or tracks used. This invention is non-adjustable except by repositioning the entire support fixture. This invention cannot prepare a tapered hole or cut.
From the foregoing, no adjustable device is known which supports a router or other type of cutting tool to generate precise cuts of virtually any desired shape, angle and depth. The present invention is fully adjustable to produce tapered cuts which may be circular, oval, spherical, or substantially rectangular.